Question

1. Most human traits do not have a clear inheritance of dominant vs. recessive from one gene, but

are polygenic…what does that mean? Name a polygenic trait

2. Some traits are X-linked. What does that mean? Name one (not colorblindness).

3. Explain red/green colorblindness

Answer 1

1- Polygenic inheritance occurs when one character is controlled by two or more genes. Often the genes are large in quantity but small in effect.

Polygenic traits-Height,Skin color,Hair color.

2- X- Linked traits- X-linked trait where a gene is located on the X-chromosome.Human and other mammals have two type chromosome X and Y.

In an X-Linked or sex linked disease,it is usually males that are affected because they have a single copy of X-chromosome that carries the mutation.

X-Linked disease: Heamophilia, Duchene's muscular dystrophy.

3- Red/Green colorblindness:- A form of colorblindness in which red & green are perceived as identical.This is most common type of color blindness.

It is inherited in an x-linked ressesive manner and affects 6% of males.it is also called Deutan colorblindness.